Equalizers

This is an image Schematic. No Description available...

This is an image Schematic. No Description available...

This is an image Schematic. No Description available...

This circuit uses a single chip, IC BA3812L for realizing a 5 band graphic equalizer for use in hi-fi audio systems.The BA3812L is a five-point graphic equalizer that has all the required functions integrated onto one IC. The IC is comprised of the five tone control circuits and input and output buffer amplifiers. The BA3812L features low distortion, low noise, and wide dynamic range, and is an ideal choice for Hi-Fi stereo applica-tions. It also has a wide operating voltage range (3.5V to 16V), which means that it can be adapted for use with most types of stereo equipment...

Because of the increasing use of digital techniques in consumer audio equipment, National has developed a digitally controlled graphic equalizer½ the LMC835. This chip replaces the potentiometers used in a conventional graphic equalizer with digitally controlled step-variable resistors, thereby allowing computer manipulation of an analog signal path. The LMC835 is configured such that a high degree of flexibility remains in the overall equalizer design, without compromising the quality of the analog signal path...

The volume control in a hi-fi amp or preamp (or any other audio device, for that matter), is a truly simple concept, right? Wrong. In order to get a smooth increase in level, the potentiometer (pot) must be logarithmic to match the non-linear characteristics of our hearing. A linear pot used for volume is quite unsatisfactory. Unless you pay serious money, the standard "log" pot you buy from electronics shops is not log at all, but is comprised of two linear sections, each with a different resistance gradient. The theory is that between the two they will make a curve which is "close enough" to log (or audio) taper. As many will have found out, this is rarely the case, and a pronounced `discontinuity` is often apparent as the control is rotated...

Audio graphic equalizers are very common as commercial products (for Hi-fi, car audio and stage use) but circuits for them are very rarely published. I didn`t design this one but it`s really very simple. The details shown are for a 7 band but the principle can be extended to almost any number of bands - if you can find accurate enough components...

The circuit of graphic equalizer, allocates ten adjusting potesometer , that each one from them affects in a predetermined area of frequencies, the central frequency of which abstains a octave (double), from the central frequencies of her neighbouring regions. Each unit has common materials with remainder and it differs only in the capacity of capacitors that constitutes the filter in each unit. When the runner of fader regulation RV1 until RV10, is in the middle then we do not have no intervention of filter above in the signal that passes from in his and gain of particular unit, is one [ X1 ]. On the contrary if the runner is moved to a side of exit, the unit acts as filter of cutting off of area and it degrades the signals of predetermined area of frequencies...

The circuit constitutes a natural extension of Mic-Line balance unit, but can be adapted to any other audio circuit. It is made up of two units in the series : A) A classic unit bass/ Treble and B) a parametric unit of mid frequencies. Both units can also be used autonomously or each one separately, with the required buffer unit, from previous and subsequent circuits. With the R2 we requlate the High frequencies +/- 18 db/oct at 20 KHZ, with R5 the Low frequencies +/- 18bd/oct at 20 KHZ, with R11 the Mid freq. +/- 15 db/oct and with R10 the center of mid freq. at 200 HZ - 6 KHZ band...